CN111917321B - Single-bus isolation bidirectional clamping ten-switch three-phase inverter topology - Google Patents

Single-bus isolation bidirectional clamping ten-switch three-phase inverter topology Download PDF

Info

Publication number
CN111917321B
CN111917321B CN202010678807.6A CN202010678807A CN111917321B CN 111917321 B CN111917321 B CN 111917321B CN 202010678807 A CN202010678807 A CN 202010678807A CN 111917321 B CN111917321 B CN 111917321B
Authority
CN
China
Prior art keywords
phase
switch tube
clamping
bridge arm
tube
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Active
Application number
CN202010678807.6A
Other languages
Chinese (zh)
Other versions
CN111917321A (en
Inventor
马海啸
兰摘星
邵鹏程
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Nanjing University of Posts and Telecommunications
Original Assignee
Nanjing University of Posts and Telecommunications
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Nanjing University of Posts and Telecommunications filed Critical Nanjing University of Posts and Telecommunications
Priority to CN202010678807.6A priority Critical patent/CN111917321B/en
Publication of CN111917321A publication Critical patent/CN111917321A/en
Application granted granted Critical
Publication of CN111917321B publication Critical patent/CN111917321B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Images

Classifications

    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M7/00—Conversion of ac power input into dc power output; Conversion of dc power input into ac power output
    • H02M7/42—Conversion of dc power input into ac power output without possibility of reversal
    • H02M7/44—Conversion of dc power input into ac power output without possibility of reversal by static converters
    • H02M7/48—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode
    • H02M7/53—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal
    • H02M7/537—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters
    • H02M7/5387—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration
    • H02M7/53871—Conversion of dc power input into ac power output without possibility of reversal by static converters using discharge tubes with control electrode or semiconductor devices with control electrode using devices of a triode or transistor type requiring continuous application of a control signal using semiconductor devices only, e.g. single switched pulse inverters in a bridge configuration with automatic control of output voltage or current
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/12—Arrangements for reducing harmonics from ac input or output
    • H02M1/126—Arrangements for reducing harmonics from ac input or output using passive filters
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/32—Means for protecting converters other than automatic disconnection
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02M—APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF
    • H02M1/00—Details of apparatus for conversion
    • H02M1/12—Arrangements for reducing harmonics from ac input or output
    • H02M1/123—Suppression of common mode voltage or current
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E10/00—Energy generation through renewable energy sources
    • Y02E10/50—Photovoltaic [PV] energy
    • Y02E10/56—Power conversion systems, e.g. maximum power point trackers

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Inverter Devices (AREA)

Abstract

The invention provides a single-bus isolation bidirectional clamping ten-switch three-phase inverter topology which comprises a photovoltaic cell panel, a traditional three-phase full-bridge inverter circuit, a three-phase output LC filter circuit, a three-phase load, a direct-current bus isolation switch tube and a clamping circuit, wherein the photovoltaic cell panel is connected with the three-phase output LC filter circuit through the three-phase load; the clamping circuit comprises a first direct current capacitor, a second direct current capacitor, a third direct current capacitor, a first clamping switch tube, a second clamping switch tube and a third clamping switch tube. The topology of the invention is added with a direct current bus isolation switch tube and a clamping circuit, so that the common mode voltage of the inverter is clamped to the voltage in a bidirectional mode in a follow current stageU d /3 or 2U d /3. Therefore, the common-mode voltage of the inverter is only in the whole inversion periodU d /3 and 2U d And 3, jumping is carried out, and the variation range is reduced, so that the leakage current suppression capability of the photovoltaic inverter is effectively improved, and the equipment and personal safety are guaranteed.

Description

Single-bus isolation bidirectional clamping ten-switch three-phase inverter topology
Technical Field
The invention relates to a photovoltaic inverter topology, in particular to a single-bus isolation bidirectional clamping ten-switch three-phase inverter topology, and belongs to the technical field of power electronic direct current-alternating current conversion.
Background
Solar photovoltaic power generation is one of the most promising renewable energy applications, and can meet future energy requirements of human beings and overcome the problem of environmental pollution. In a photovoltaic power generation system, an inverter is one of indispensable entities, and is usually provided with a high-frequency or power-frequency transformer, and the existence of the transformer realizes the electrical isolation between a photovoltaic cell panel and a power grid, thereby playing an important role in ensuring personal safety. In addition, the use of the transformer reduces the direct current component injected into the power grid, and is beneficial to improving the power quality of the power grid. However, the presence of the transformer reduces the conversion efficiency of the system, increasing the size, weight and cost of the overall system. The inverter without transformer has a small size, a light weight, a low cost, a high efficiency, and the like, and thus has become a hot spot of domestic and international research in recent years. However, stray parasitic capacitances exist between the photovoltaic panel and the ground, and due to the lack of electrical isolation of the transformer, leakage currents are caused by the common mode voltage with high frequency variations acting on the parasitic capacitances. The leakage current can cause electromagnetic interference, affect the output quality of electric energy, and even cause equipment damage and harm to personal safety. Therefore, according to the German VDE-0126-1-1 standard, the value of the leakage current must be limited to a certain range.
Compared with the Chinese patent with the patent number of 2018101449302/2019106753445, the invention omits a direct current bus switch and adds a clamping switch. The direct current bus switch bears all conversion power of the inverter, so that the current flowing through the direct current bus switch is large, the on-state loss and the switching loss of the direct current bus switch are large, and the total power loss of the switch is large. However, the clamping switch only provides a clamping effect and does not participate in power exchange of the inverter, the current flowing through the clamping switch is approximately zero, and the on-state loss and the switching loss of the clamping switch are small, so that the total power loss of the clamping switch is small. In conclusion, the scheme of replacing one direct current bus switch with one clamping switch is beneficial to reducing the loss of the switching device of the inverter and improving the efficiency of the inverter.
Disclosure of Invention
The invention aims to solve the technical problem that the defects of a three-phase photovoltaic inverter in the prior art in the aspect of leakage current suppression technology are overcome, and a single-bus isolation bidirectional clamping ten-switch three-phase inverter topology is provided.
The invention provides a single-bus isolation bidirectional clamping ten-switch three-phase inverter topology which comprises a photovoltaic cell panel, a traditional three-phase full-bridge inverter circuit, a three-phase output LC filter circuit and a three-phase load, wherein the traditional three-phase full-bridge inverter circuit comprises an A-phase upper bridge arm switch tube, an A-phase lower bridge arm switch tube, a B-phase upper bridge arm switch tube, a B-phase lower bridge arm switch tube, a C-phase upper bridge arm switch tube and a C-phase lower bridge arm switch tube. The inverter topology also comprises a direct current bus isolating switch tube and a clamping circuit; the clamping circuit comprises a first direct current capacitor, a second direct current capacitor, a third direct current capacitor, a first clamping switch tube, a second clamping switch tube and a third clamping switch tube; the positive electrode of the photovoltaic cell panel is respectively connected with the positive electrode of a first direct current capacitor and the collector electrode of a direct current bus isolating switch tube, the negative electrode of the photovoltaic cell panel is connected with the negative electrode of a third direct current capacitor, the emitting electrode of an A-phase lower bridge arm switch tube, the emitting electrode of a B-phase lower bridge arm switch tube and the emitting electrode of a C-phase lower bridge arm switch tube at a point Q, the negative electrode of the first direct current capacitor is respectively connected with the positive electrode of a second direct current capacitor and the emitting electrode of a second clamping switch tube, the negative electrode of the second direct current capacitor is respectively connected with the positive electrode of a third direct current capacitor and the emitting electrode of a third clamping switch tube, the emitting electrode of the direct current bus isolating switch tube is respectively connected with the emitting electrode of a first clamping switch tube, the collector electrode of the third clamping switch tube, the collector electrode of an A-phase upper bridge arm switch tube, the collector electrode of a B-phase upper bridge arm switch tube and the collector electrode of a C-phase upper bridge arm switch tube, and the collector electrode of the second clamping switch tube is connected with the collector electrode of the first clamping switch tube.
The invention adds a direct current bus isolation switch tube and a clamping circuit on the basis of the traditional three-phase inverter topology. The direct current bus isolating switch tube is positioned between the positive electrode of the photovoltaic cell panel and the common point of the three-phase upper bridge arm switch tubes and is an alternating current side isolating switch tube and a direct current side isolating switch tube, and when the inverter is in a follow current stage, the alternating current side and the direct current side of the inverter can be decoupled. The clamping circuit comprises three voltage-dividing capacitors and three clamping switch tubes, wherein the voltage-dividing capacitors divide the DC input into 0 and U d /3、2U d 3 and U d Four voltage classes (U) d Representing the output voltage of the photovoltaic panel). At U d Two clamping switch tubes are added between the/3 potential point and the common point of the upper bridge arm switch tube, and 2U d A clamping switch tube is added between a/3 potential point and the common point of the upper bridge arm switch tube, the clamping switch tubes ensure that the voltage dividing capacitor cannot be short-circuited, and the common-mode voltage of the inverter can be bidirectionally clamped to U according to the control requirement d /3 or 2U d /3. Therefore, the amplitude of the common-mode voltage of the inverter varies within a range of U during the whole inversion period d /3～2U d /3, together withThe mode voltage fluctuation is reduced, the leakage current is effectively inhibited, the electromagnetic interference of the system is reduced, and meanwhile, the equipment and personal safety is guaranteed.
The technical scheme for further optimizing the invention is as follows:
furthermore, the three-phase output LC filter circuit comprises an A-phase filter inductor, a B-phase filter inductor, a C-phase filter inductor, an A-phase filter capacitor, a B-phase filter capacitor and a C-phase filter capacitor.
Further, the three-phase load comprises an A-phase load, a B-phase load and a C-phase load.
Further, an emitting electrode of the phase a upper bridge arm switching tube, a collector electrode of the phase a lower bridge arm switching tube and one end of the phase a filter inductor are connected to a point a, an emitting electrode of the phase B upper bridge arm switching tube, a collector electrode of the phase B lower bridge arm switching tube and one end of the phase B filter inductor are connected to a point B, and an emitting electrode of the phase C upper bridge arm switching tube, a collector electrode of the phase C lower bridge arm switching tube and one end of the phase C filter inductor are connected to a point C.
Furthermore, the other end of the A-phase filter inductor is connected with the anode of the A-phase filter capacitor and one end of the A-phase load respectively, the other end of the B-phase filter inductor is connected with the anode of the B-phase filter capacitor and one end of the B-phase load respectively, and the other end of the C-phase filter inductor is connected with the anode of the C-phase filter capacitor and one end of the C-phase load respectively.
Furthermore, the negative electrode of the phase a filter capacitor is connected to the negative electrode of the phase B filter capacitor, the negative electrode of the phase C filter capacitor, the other end of the phase a load, the other end of the phase B load, and the other end of the phase C load at a point N (referenced to ground).
Further, through the action of the direct current bus isolation switch tube and the clamping circuit, the common-mode voltage of the inverter is clamped to the U-shaped voltage in the follow current stage in a bidirectional mode d /3 or 2U d /3；
In the whole inversion period, the expression of the common-mode voltage is as follows:
u cm ＝(u AQ +u BQ +u CQ )/3
wherein u is cm Is the common mode voltage of the inverter, u AQ Is point APotential difference from point Q, u BQ Is the potential difference between B point and Q point, u CQ Is the potential difference between the point C and the point Q.
By adopting the structure, the three clamping switch tubes can not cause the short circuit of the voltage division capacitor under various working states.
In the present invention, the switching state of the inverter is defined as [ M ] 1 ,M 2 ,M 3 ,M 4 ,M 5 ](ii) a Wherein M is 1 Representing the switching state of the switching tube of the A-phase bridge arm, M 1 1 represents that the switching tube of the upper bridge arm of the A phase is switched on and the switching tube of the lower bridge arm is switched off, and M 1 When the phase A is equal to 0, the switching tube of the upper bridge arm is switched off, and the switching tube of the lower bridge arm is switched on; m 2 Representing the switching state of the B-phase bridge arm switching tube, M 2 1 represents that the switching tube of the upper bridge arm of the B phase is conducted and the switching tube of the lower bridge arm is turned off, and M 2 When the phase B is equal to 0, the upper bridge arm switching tube is switched off, and the lower bridge arm switching tube is switched on; m 3 Representing the switching state of the C-phase bridge arm switching tube, M 3 1 represents that the C-phase upper bridge arm switching tube is conducted and the lower bridge arm switching tube is turned off, and M 3 When the phase is equal to 0, the switching tube of the upper bridge arm of the C phase is turned off, and the switching tube of the lower bridge arm is turned on; m 4 Indicating the on-off state of the DC bus-bar disconnector tube, M 4 1 denotes the direct current bus disconnector tube on, M 4 When the direct current bus disconnecting switch tube is turned off, 0 is defined as the direct current bus disconnecting switch tube; m 5 Representing the switching state of three clamping switch tubes, M 5 1 means that the first clamping switch tube and the second clamping switch tube are conducted and the third clamping switch tube is turned off, M 5 0 represents that the first clamping switch tube and the second clamping switch tube are turned off and the third clamping switch tube is turned on; m 5 And Z represents that the three clamping switch tubes are all turned off.
Further, the six normal operating modes of the inverter are respectively as follows: [1,0,0,1, Z ], [1,1,0,1, Z ], [0,1,1,1, Z ], [0,0,1,1, Z ] and [1,0,1,1, Z ], and the two freewheel modes are [1,1,1,0,1] and [1,1,1,0,0] respectively.
Compared with the prior art, the invention adopting the technical scheme has the following technical effects: the number of the used direct current bus switches is small, so that the total loss of the switch devices of the inverter is reduced, and the inversion is improvedThe efficiency of the device. The addition of the DC bus isolation switch tube and the clamping circuit ensures that the common-mode voltage of the inverter is clamped to the U in a bidirectional way in the follow current stage d /3 or 2U d /3. Therefore, the common-mode voltage of the inverter is only U in the whole inversion period d /3 and 2U d And 3, jumping is carried out, and the variation range is reduced, so that the leakage current suppression capability of the photovoltaic inverter is effectively improved, and the equipment and personal safety are guaranteed.
Drawings
The invention is further described below with reference to the accompanying drawings.
Fig. 1 is a main circuit configuration diagram of the present invention.
FIG. 2 is a diagram illustrating a mode one according to the present invention.
Fig. 3 is a schematic diagram of mode two according to the present invention.
Fig. 4 is a schematic diagram of mode three of the present invention.
Fig. 5 is a schematic diagram of mode four of the present invention.
Fig. 6 is a schematic diagram of mode five of the present invention.
Fig. 7 is a schematic diagram of mode six of the present invention.
Fig. 8 is a schematic diagram of mode seven of the present invention.
FIG. 9 is a schematic diagram of mode eight of the present invention.
FIG. 10 is a timing diagram of driving signals and a common mode voltage thereof according to the present invention.
Detailed Description
The technical scheme of the invention is further explained in detail by combining the drawings as follows: the present embodiment is implemented on the premise of the technical solution of the present invention, and a detailed implementation manner and a specific operation process are given, but the protection authority of the present invention is not limited to the following embodiments.
The embodiment provides a single-bus isolation bidirectional clamping ten-switch three-phase inverter topology, the structure of which is shown in fig. 1, and the topology comprises a photovoltaic cell panel PV, a traditional three-phase full-bridge inverter circuit, a three-phase output LC filter circuit, a three-phase load and a direct-current bus isolation switch tube S 7 And a clamping circuit. The traditional three-phase full-bridge inverter circuit comprises an A-phase upper bridge armSwitch tube S 1 Phase A lower bridge arm switch tube S 4 B phase upper bridge arm switch tube S 3 B phase lower bridge arm switch tube S 6 C-phase upper bridge arm switch tube S 5 And C-phase lower bridge arm switching tube S 2 . The three-phase output LC filter circuit comprises an A-phase filter inductor L a B-phase filter inductor L b C-phase filter inductor L c Phase A filter capacitor C a B phase filter capacitor C b And C phase filter capacitor C c . The three-phase load comprises an A-phase load R a B phase load R b And C phase load R c . The clamping circuit comprises a first DC capacitor C 1 A second DC capacitor C 2 A third DC capacitor C 3 First clamping switch tube S 8 A second clamping switch tube S 9 And a third clamping switch tube S 10 . Wherein, the positive pole of the photovoltaic cell panel PV is respectively connected with the first direct current capacitor C 1 Positive electrode, dc bus isolating switch tube S 7 Is connected with the collector of the photovoltaic cell panel PV, the negative pole of the photovoltaic cell panel PV is connected with the third direct current capacitor C 3 Negative electrode of (1), A phase lower bridge arm switch tube S 4 Emitter and B-phase lower bridge arm switch tube S 6 Emitter and C-phase lower bridge arm switch tube S 2 Is connected to a point Q, a first direct current capacitor C 1 Respectively with a second DC capacitor C 2 Positive electrode of the first clamping switch tube S 9 Is connected to a second DC capacitor C 2 Respectively with a third DC capacitor C 3 Positive pole of S, third clamping switch tube S 10 The emitting electrodes of the two-way isolating switch are connected, and a direct current bus isolating switch tube S 7 Respectively with the first clamping switch tube S 8 Emitter and third clamping switch tube S 10 Collector and A phase upper bridge arm switch tube S 1 Collector and B phase upper bridge arm switch tube S 3 Collector and C-phase upper bridge arm switching tube S 5 Is connected with the collector of the second clamping switch tube S 9 Collector and first clamping switch tube S 8 The collectors of the A-phase upper bridge arm switching tubes S are connected 1 Emitter and A-phase lower bridge arm switch tube S 4 Collector electrode, A phase filter inductor L a One end of the first and second phase connecting to the point A, B upper bridge arm switch tube S 3 Emitter and B-phase lower bridge arm switch tube S 6 Collector electrode, B-phase filter inductor L b One end of the upper bridge arm switch tube S is connected with the point B and the C phase 5 Emitter and C-phase lower bridge arm switching tube S 2 Collector electrode, C phase filter inductor L c One end of the first and second phase-connected filter inductors L is connected with the point C, A phase filter inductor L a The other end of the first and second phase filter capacitors are respectively connected with an A phase filter capacitor C a Positive electrode of (2), A phase load R a Is connected with one end of the B-phase filter inductor L b The other end of the first and second phase filter capacitors are respectively connected with a B-phase filter capacitor C b Positive electrode of (2), B phase load R b Is connected with one end of the C-phase filter inductor L c The other end of the first and second phase capacitors are respectively connected with a C-phase filter capacitor C c Positive electrode of (2), C phase load R c Is connected with one end of the A-phase filter capacitor C a Negative pole of (2) and B phase filter capacitor C b Negative pole, C phase filter capacitor C c Negative electrode of (1), A phase load R a The other end of (2), B-phase load R b The other end of (1), C-phase load R c The other end of which is connected to point N (referenced to ground). The three clamping switch tubes can not cause the short circuit of the voltage division capacitor under various working states.
Isolating switch tube S through direct current bus 7 And the clamping circuit is used for clamping the common-mode voltage of the inverter to U in a bidirectional mode in a freewheeling stage d /3 or 2U d /3. In the whole inversion period, the expression of the common-mode voltage is as follows:
u cm ＝(u AQ +u BQ +u CQ )/3
wherein u is cm Is the common-mode voltage of the inverter, u AQ Is the potential difference between the point A and the point Q, u BQ Is the potential difference between B point and Q point, u CQ Is the potential difference between the point C and the point Q.
Defining the switching state of the inverter as [ M 1 ,M 2 ,M 3 ,M 4 ,M 5 ]. Wherein M is 1 Showing the switching state of the A-phase bridge arm switching tube, M 1 1 represents the switching tube S of the upper bridge arm of the a phase 1 Conducting lower bridge arm switch tube S 4 Off, M 1 0 represents the switching tube S of the upper bridge arm of the A phase 1 Switch tube S of turn-off and lower bridge arm 4 And conducting. M 2 Represents a B phaseSwitching state of bridge arm switching tube, M 2 B-phase upper arm switching tube S is represented by 1 3 Conducting lower bridge arm switch tube S 6 Off, M 2 0 represents the switching tube S of the upper bridge arm of the B phase 3 Switch tube S of turn-off lower bridge arm 6 And conducting. M 3 Representing the switching state of the C-phase bridge arm switching tube, M 3 1 denotes a C-phase upper arm switching tube S 5 Conducting lower bridge arm switch tube S 2 Off, M 3 0 represents the C-phase upper arm switching tube S 5 Switch tube S of turn-off lower bridge arm 2 And conducting. M 4 Indicating the switching state of the disconnector tube, M 4 D.c. bus-bar disconnector tube S is denoted by 1 7 On, M 4 D.c. bus isolating switch tube S is represented by 0 7 And (6) turning off. M 5 Representing the switching state of three clamping switch tubes, M 5 1 denotes a first clamping switch S 8 And a second clamping switch tube S 9 Conducting and third clamping switch tube S 10 Off, M 5 0 denotes the first clamping switch tube S 8 And a second clamping switch tube S 9 Turn-off and third clamping switch tube S 10 And conducting. M 5 And Z represents that the three clamping switch tubes are all turned off.
Therefore, the six normal operating modes of the inverter are: [1,0,0,1, Z ], [1,1,0,1, Z ], [0,1,1,1, Z ], [0,0,1,1, Z ] and [1,0,1,1, Z ], and the two freewheel modes are [1,1,1,0,1] and [1,1,1,0,0] respectively. The above modes are shown in fig. 2 to 9, and the operation principle of the inverter in each mode is briefly analyzed as follows:
the first mode is as follows: as shown in FIG. 2, the inverter switching states are [1,0,0,1, Z]Switching tube S 1 、S 6 、S 2 And S 7 The voltage between the gate and the emitter of (1) is high level, they are in conducting state; switch tube S 3 、S 5 、S 4 、S 8 、S 9 And S 10 Are low, they are in an off state. The current flows out from the positive electrode of the photovoltaic cell panel PV and flows through S 7 —S 1 —L a —R a —N—R b 、R c —L b 、L c —S 6 、S 2 And then back to the negative pole of the photovoltaic panel PV. At this time, u is due to AQ ＝U d ，u BQ ＝u CQ When it is 0, the common mode voltage is:
u cm ＝(u AQ +u BQ +u CQ )/3＝U d /3。
mode two: as shown in FIG. 3, the inverter switching states are [1,1,0,1, Z]Switching tube S 1 、S 3 、S 2 And S 7 The voltage between the gate and the emitter of (1) is high level, they are in conducting state; switch tube S 5 、S 4 、S 6 、S 8 、S 9 And S 10 Are low, they are in an off state. The current flows from the positive electrode of the photovoltaic cell panel PV and flows through S 7 —S 1 、S 3 —L a 、L b —R a 、R b —N—R c —L c —S 2 And then back to the negative electrode of the photovoltaic panel PV. At this time, u is due to AQ ＝u BQ ＝U d ，u CQ When it is 0, the common mode voltage is:
u cm ＝(u AQ +u BQ +u CQ )/3＝2U d /3。
a third mode: as shown in FIG. 4, the inverter switching states are [0,1,0,1, Z]Switching tube S 3 、S 4 、S 2 And S 7 The voltage between the gate and the emitter of (1) is high level, they are in conducting state; switch tube S 1 、S 5 、S 6 、S 8 、S 9 And S 10 Are low, they are in an off state. The current flows from the positive electrode of the photovoltaic cell panel PV and flows through S 7 —S 3 —L b —R b —N—R a 、R c —L a 、L c —S 4 、S 2 And then back to the negative electrode of the photovoltaic panel PV. At this time, u is due to BQ ＝U d ，u AQ ＝u CQ 0, so the common mode voltage is:
u cm ＝(u AQ +u BQ +u CQ )/3＝U d /3。
and a fourth mode: as shown in FIG. 5, the inverter switching states are [0,1,1,1, Z]Switching tube S 3 、S 5 、S 4 And S 7 The voltage between the gate and the emitter of (1) is high level, they are in conducting state; switch tube S 1 、S 6 、S 2 、S 8 、S 9 And S 10 Are low, they are in an off state. The current flows from the positive electrode of the photovoltaic cell panel PV and flows through S 7 —S 3 、S 5 —L b 、L c —R b 、R c —N—R a —L a —S 4 And then back to the negative electrode of the photovoltaic panel PV. At this time, u is due to BQ ＝u CQ ＝U d ，u AQ When it is 0, the common mode voltage is:
u cm ＝(u AQ +u BQ +u CQ )/3＝2U d /3。
a fifth mode: as shown in FIG. 6, the inverter switching states are [0,0,1,1, Z]Switching tube S 5 、S 4 、S 6 And S 7 The voltage between the gate and the emitter of (1) is high level, they are in conducting state; switch tube S 1 、S 3 、S 2 、S 8 、S 9 And S 10 The voltage between the gate and the emitter of (a) is low and they are in an off state. The current flows from the positive electrode of the photovoltaic cell panel PV and flows through S 7 —S 5 —L c —R c —N—R a 、R b —L a 、L b —S 4 、S 6 And then back to the negative electrode of the photovoltaic panel PV. At this time, u is due to CQ ＝U d ，u AQ ＝u BQ When it is 0, the common mode voltage is:
u cm ＝(u AQ +u BQ +u CQ )/3＝U d /3。
a sixth mode: as shown in FIG. 7, the inverter switching states are [1,0,1,1, Z]Switching tube S 1 、S 5 、S 6 And S 7 The voltage between the gate and the emitter of (1) is high level, they are in conducting state; switch tube S 3 、S 4 、S 2 、S 8 、S 9 And S 10 Are low, they are in an off state. The current flows from the positive electrode of the photovoltaic cell panel PV and flows through S 7 —S 1 、S 5 —L a 、L c —R a 、R c —N—R b —L b —S 6 And then back to the negative pole of the photovoltaic panel PV. At this time, u is due to AQ ＝u CQ ＝U d ，u BQ 0, so the common mode voltage is:
u cm ＝(u AQ +u BQ +u CQ )/3＝2U d /3。
a seventh mode: as shown in FIG. 8, the inverter switching states are [1,1,1,0,1]]Switching tube S 1 、S 3 、S 5 、S 8 And S 9 The voltage between the gate and the emitter of (1) is high level, they are in conducting state; switch tube S 4 、S 6 、S 2 、S 7 And S 10 Are low, they are in an off state. The former state of the mode is generally that two of three switching tubes of the upper bridge arm are conducted, and the mode two enters the mode seven, which is taken as an example, and other conditions are similar. At the moment, the circuit enters a follow current stage, and current flows through S in sequence 1 、S 3 —L a 、L b —R a 、R b —N—R c —L c —S 5 When the photovoltaic cell panel PV is disconnected with the AC side, the clamping switch tube S 8 、S 9 Conduction causes the potential difference between the point A, B and the point C relative to the point Q to be clamped to 2U d And/3, namely:
u AQ ＝u BQ ＝u CQ ＝2U d /3，
so that the common mode voltage u cm ＝(u AQ +u BQ +u CQ )/3＝2U d /3。
The mode eight: as shown in figure 9 of the drawings,inverter switching state is [1,1,1, 0%]Switching tube S 1 、S 3 、S 5 And S 10 The voltage between the gate and the emitter of (1) is high level, they are in conducting state; switch tube S 4 、S 6 、S 2 、S 7 、S 8 And S 9 The voltage between the gate and the emitter of (a) is low and they are in an off state. The former state of the mode is generally that two of three switching tubes of the lower bridge arm are conducted, and here, the mode one enters the mode eight, and other conditions are similar. At the moment, the circuit enters a follow current stage, and current flows through S in sequence 1 —L a —R a —N—R b 、R c —L b 、L c —S 3 、S 5 The photovoltaic cell panel PV is disconnected with the alternating current side, and the third clamping switch tube S 10 Conduction causes the potential difference between point A, B and point C relative to point Q to be clamped to U d And/3, namely:
u AQ ＝u BQ ＝u CQ ＝U d /3，
so that the common mode voltage u cm ＝(u AQ +u BQ +u CQ )/3＝U d /3。
Fig. 10 shows a timing diagram of driving signals and corresponding common mode voltage values in a control scheme, where the waveforms are, from top to bottom: three-way sine modulation wave u with 120-degree phase difference ra 、u rb 、u rc And a triangular carrier u c (ii) a A-phase upper bridge arm switch tube S 1 Of the gate and emitter voltage waveform u g1 (ii) a A-phase lower bridge arm switch tube S 4 Of the gate and emitter of g4 (ii) a B-phase upper bridge arm switch tube S 3 Of the gate and emitter of g3 (ii) a B-phase lower bridge arm switch tube S 6 Of the gate and emitter voltage waveform u g6 (ii) a C-phase upper bridge arm switch tube S 5 Of the gate and emitter of g5 (ii) a C-phase lower bridge arm switch tube S 2 Of the gate and emitter of g2 (ii) a DC bus isolation switch tube S 7 Of the gate and emitter of g7 (ii) a Clamping switch tube S 8 And S 9 Of the gate and emitter of g89 (ii) a Third clamping switch tube S 10 Of the gate and emitter voltage waveform u g10 (ii) a Common mode voltage waveform u of an inverter cm 。
From the above analysis, it can be seen that the common-mode voltage of the inverter is clamped to U bidirectionally during freewheeling d /3 or 2U d /3. Therefore, the common mode voltage is only in U during the whole inversion period d /3 and 2U d And 3, jumping is carried out, the change range is reduced, the leakage current is effectively inhibited, the electromagnetic interference of a system is reduced, the electric energy quality is improved, and meanwhile, the equipment and personal safety is guaranteed.
In conclusion, the transformer-free three-phase photovoltaic inverter can effectively reduce the technical problem of large common-mode voltage fluctuation of the transformer-free three-phase photovoltaic inverter, provides a method for inhibiting leakage current of the transformer-free three-phase photovoltaic inverter, and has a certain engineering application value.
The above description is only an embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art can understand that the modifications or substitutions within the technical scope of the present invention are included in the scope of the present invention, and therefore, the scope of the present invention should be subject to the protection scope of the claims.

Claims (7)

1. A single-bus isolation bidirectional clamping ten-switch three-phase inverter topology comprises a photovoltaic cell Panel (PV), a three-phase full-bridge inverter circuit, a three-phase output LC filter circuit and a three-phase load, wherein the three-phase full-bridge inverter circuit comprises an A-phase upper bridge arm switch tube (S) 1 ) Phase A lower bridge arm switch tube (S) 4 ) B phase upper bridge arm switch tube (S) 3 ) B phase lower bridge arm switch tube (S) 6 ) C phase upper bridge arm switch tube (S) 5 ) And C phase lower bridge arm switch tube (S) 2 ) (ii) a The method is characterized in that: also comprises a DC bus isolating switch tube (S) 7 ) And a clamping circuit; the clamping circuit comprises a first DC capacitor (C) 1 ) A second DC capacitor (C) 2 ) A third DC capacitor (C) 3 ) The first clamping switch tube (S) 8 ) A second clamping switch tube (S) 9 ) And a third clamping switch tube (S) 10 ) (ii) a The positive electrode of the photovoltaic cell panel is respectively connected with a first direct current capacitor (C) 1 ) Positive electrode, DC bus bar isolation switch tube (S) 7 ) Is connected with the collector of the photovoltaic cell panel, the negative electrode of the photovoltaic cell panel is connected with a third direct current capacitor (C) 3 ) Negative pole of (1), A phase lower arm switching tube (S) 4 ) Emitter, B-phase lower arm switch tube (S) 6 ) Emitter, C-phase lower bridge arm switch tube (S) 2 ) Is connected to a point Q, said first dc capacitor (C) 1 ) Respectively with a second direct current capacitor (C) 2 ) Positive pole of the first clamping switch tube (S), the second clamping switch tube (S) 9 ) Is connected to the emitter of the first direct current capacitor (C), the second direct current capacitor (C) 2 ) Respectively with a third DC capacitor (C) 3 ) Positive pole of (S), third clamping switch tube (S) 10 ) Is connected with the emitting electrode of the direct current bus isolating switch tube (S) 7 ) Respectively with the first clamping switch tube (S) 8 ) Emitter of (2), third clamping switch tube (S) 10 ) Collector electrode, A phase upper bridge arm switch tube (S) 1 ) Collector electrode, B phase upper bridge arm switch tube (S) 3 ) Collector, C phase upper bridge arm switch tube (S) 5 ) Is connected to the collector of the second clamping switch tube (S) 9 ) Collector and first clamping switch tube (S) 8 ) Is connected to the collector of the collector.
2. The single bus isolated bi-directional clamped ten-switch three-phase inverter topology of claim 1, wherein: the three-phase output LC filter circuit comprises an A-phase filter inductor (L) a ) B phase filter inductor (L) b ) C phase filter inductor (L) c ) Phase A filter capacitor (C) a ) Phase B filter capacitor (C) b ) And a C-phase filter capacitor (C) c )。
3. The single bus isolated bi-directional clamped ten-switch three-phase inverter topology of claim 1, wherein: the three-phase load comprises an A-phase load (R) a ) Phase B load (R) b ) And C phase load (R) c )。
4. The single bus isolated bi-directional clamped ten-switch three-phase inverter topology of claim 1, wherein: the A-phase upper bridge arm switch tube (S) 1 ) Emitter of (2) and A phase lower bridge arm switching tube (S) 4 ) Collector electrode, A phase filter inductor (L) a ) Is connected to the point A, and the B phase upper bridge arm switch tube (S) 3 ) Emitter of (2) and B phase lower bridge arm switch tube (S) 6 ) Collector electrode, B-phase filter inductor (L) b ) Is connected to a point B, and the C-phase upper bridge arm switching tube (S) 5 ) Emitter and C-phase lower bridge arm switching tube (S) 2 ) Collector electrode, C phase filter inductor (L) c ) One end of which is connected to point C; the A-phase filter inductor (L) a ) The other end of the filter is respectively connected with an A-phase filter capacitor (C) a ) Positive electrode of (2), A phase load (R) a ) Is connected to the B-phase filter inductor (L) b ) The other end of the first and second phase filter capacitors are respectively connected with a B-phase filter capacitor (C) b ) Positive electrode of (2), B phase load (R) b ) Is connected to one end of the C-phase filter inductor (L) c ) The other ends of the two-phase filter are respectively connected with a C-phase filter capacitor (C) c ) Positive electrode of (2), C phase load (R) c ) One end of the two ends are connected; the A-phase filter capacitor (C) a ) Negative pole of (2) and B phase filter capacitor (C) b ) Negative electrode of (2), C phase filter capacitor (C) c ) Negative electrode of (2), A phase load (R) a ) The other end of (2), B-phase load (R) b ) The other end of (C), a C-phase load (R) c ) The other end of which is connected to point N.
5. The single bus isolated bi-directional clamped ten-switch three-phase inverter topology of claim 4, wherein: isolating the switch tube (S) by the direct current bus 7 ) And the clamping circuit is used for clamping the common-mode voltage of the inverter to U in a freewheeling stage in a bidirectional mode d /3 or 2U d /3；U d Representing the output voltage of the photovoltaic panel;
in the whole inversion period, the expression of the common-mode voltage is as follows:
u cm ＝(u AQ +u BQ +u CQ )/3
wherein u is cm Is the common mode voltage of the inverter, u AQ Is the potential difference between point A and point Q, u BQ Is the potential difference between point B and point Q, u CQ Is the potential difference between point C and point Q.
6. The single bus isolated bi-directional clamped ten-switch three-phase inverter topology of claim 1, wherein: defining the switching state of the inverter as [ M 1 ,M 2 ,M 3 ,M 4 ,M 5 ](ii) a Wherein M is 1 Representing the switching state of the switching tube of the A-phase bridge arm, M 1 1 denotes an a-phase upper arm switching tube (S) 1 ) Conducting and lower bridge arm switch tube (S) 4 ) Off, M 1 0 denotes an a-phase upper arm switching tube (S) 1 ) Switch tube of lower bridge arm (S) is turned off 4 ) Conducting; m 2 Representing the switching state of the B-phase bridge arm switching tube, M 2 1 represents a B-phase upper arm switching tube (S) 3 ) Conducting and lower bridge arm switch tube (S) 6 ) Off, M 2 0 denotes a B-phase upper arm switching tube (S) 3 ) Switch tube of lower bridge arm (S) is turned off 6 ) Conducting; m 3 Representing the switching state of the C-phase bridge arm switching tube, M 3 1 denotes a C-phase upper arm switching tube (S) 5 ) Conducting and lower bridge arm switch tube (S) 2 ) Off, M 3 0 denotes a C-phase upper arm switching tube (S) 5 ) Switch-off and lower bridge arm switch tube (S) 2 ) Conducting; m 4 Indicating the switching state of the disconnector tube, M 4 1 denotes a dc bus disconnector tube (S) 7 ) On, M 4 D.c. bus bar disconnecting switch tube (S) is represented by 0 7 ) Turning off; m 5 Representing the switching state of three clamping switch tubes, M 5 1 denotes a first clamping switch (S) 8 ) And a second clamping switch tube (S) 9 ) Conducting and third clamping switch tube (S) 10 ) Off, M 5 0 denotes a first clamp switch (S) 8 ) And a second clamping switch tube (S) 9 ) Turn-off and third clamping switch tube (S) 10 ) Conducting; m 5 And Z represents that the three clamping switch tubes are all turned off.
7. The single bus isolation bi-directional clamping ten-switch three-phase inverter topology of claim 6, wherein six normal operating modes of the inverter are: [1,0,0,1, Z ], [1,1,0,1, Z ], [0,1,1,1, Z ], [0,0,1,1, Z ] and [1,0,1,1, Z ], and the two freewheel modes are [1,1,1,0,1] and [1,1,1,0,0] respectively.
CN202010678807.6A 2020-07-15 2020-07-15 Single-bus isolation bidirectional clamping ten-switch three-phase inverter topology Active CN111917321B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202010678807.6A CN111917321B (en) 2020-07-15 2020-07-15 Single-bus isolation bidirectional clamping ten-switch three-phase inverter topology

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202010678807.6A CN111917321B (en) 2020-07-15 2020-07-15 Single-bus isolation bidirectional clamping ten-switch three-phase inverter topology

Publications (2)

Publication Number Publication Date
CN111917321A CN111917321A (en) 2020-11-10
CN111917321B true CN111917321B (en) 2022-08-23

Family

ID=73280947

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202010678807.6A Active CN111917321B (en) 2020-07-15 2020-07-15 Single-bus isolation bidirectional clamping ten-switch three-phase inverter topology

Country Status (1)

Country Link
CN (1) CN111917321B (en)

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108390583A (en) * 2018-02-12 2018-08-10 南京邮电大学 One kind ten switchs the non-isolated photovoltaic DC-to-AC converter topological structure of Clamp three-phase
CN110460259A (en) * 2019-07-25 2019-11-15 南京邮电大学 Ten switch of one kind staggeredly clamps three-phase photovoltaic inverter topological structure

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN103812359B (en) * 2014-01-16 2016-08-17 深圳市保益新能电气有限公司 A kind of ac-dc conversion circuit and control method thereof
CN108702104B (en) * 2015-11-06 2020-06-16 汪洪亮 Five-level inverter topology circuit and three-phase five-level inverter topology circuit

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN108390583A (en) * 2018-02-12 2018-08-10 南京邮电大学 One kind ten switchs the non-isolated photovoltaic DC-to-AC converter topological structure of Clamp three-phase
CN110460259A (en) * 2019-07-25 2019-11-15 南京邮电大学 Ten switch of one kind staggeredly clamps three-phase photovoltaic inverter topological structure

Also Published As

Publication number Publication date
CN111917321A (en) 2020-11-10

Similar Documents

Publication Publication Date Title
CN110460259B (en) Ten-switch staggered clamping three-phase photovoltaic inverter topological structure
CN102624274A (en) Interleaving parallel grid-connected inverter and control method thereof
CN102005954B (en) Single-phase non-isolated photovoltaic grid-connected inverter and control method
CN108390584B (en) Control method of ten-switch clamping type three-phase non-isolated photovoltaic inverter
CN105939126B (en) A kind of quasi- Z-source inverter of switched inductors type mixing
CN102088252B (en) Inverter without transformer realized by switched capacitor and applications of inverter
CN105262361A (en) Two-stage non-isolation photovoltaic grid-connected inverter and control method thereof
CN102684522A (en) Non-isolated photovoltaic grid-connected inverter and control method thereof
CN102882228A (en) Single-phase non-isolated photovoltaic grid-connected inverter
CN212033777U (en) Improved non-isolated photovoltaic inverter device
CN111327222B (en) Current conversion circuit
CN111917321B (en) Single-bus isolation bidirectional clamping ten-switch three-phase inverter topology
CN108233756B (en) A kind of single input is double to be grounded half-bridge inverter and its control method
CN108390583B (en) One kind ten switchs the non-isolated photovoltaic DC-to-AC converter topological structure of Clamp three-phase
CN102412748B (en) Grid-connected inverter and control method thereof
CN201994870U (en) Non-transformer inverter achieved by switch capacitor
CN104539180A (en) Single-phase transformer-free inverter capable of reducing system leak current
CN204928612U (en) Photovoltaic power generation device with auxiliary resonant circuit
CN104167946A (en) Midpoint clamping type single-phase non-isolated photovoltaic inverter main circuit topology with follow current switch
CN111917322B (en) Control method of single-bus isolation bidirectional clamping ten-switch three-phase inverter
CN112104249B (en) Non-isolated inverter device, control method thereof and photovoltaic system with non-isolated inverter device
Cai et al. Highly Reliable Dual-ground Lift-voltage PV Grid-connected Inverter
CN110896285B (en) Non-isolation clamping type three-phase Heric photovoltaic inverter topology
WO2013163777A1 (en) Non-isolated photovoltaic grid-connected inverter and control method therefor
CN108365769A (en) A kind of single input is double to be grounded asymmetrical half-bridge inverter and its control method

Legal Events

Date Code Title Description
PB01 Publication
PB01 Publication
SE01 Entry into force of request for substantive examination
SE01 Entry into force of request for substantive examination
GR01 Patent grant
GR01 Patent grant